thompson



Ja 1956 w. N. THOMPSON STRAIGHT PULL JAR Filed July 9, 1953 M41. 75? 7A 0MP50A/ INVENTOR.

United States Patent STRAIGHT PULL JAR Walter N. Thompson, Santa Fe Springs, Calif. Application July 9, 1953, Serial No. 367,071 Claims. (Cl. 255--27) This invention relates to a straight pull jar adapted to be used in the drilling of oil wells and the like, to recover lost fish, loose and stuck pipe, and the like.

A primary object of the invention is to provide an improved jar consisting principally of two telescopically arranged parts capable of a limited axial movement relatively to each other and having a restraining means which will permit, but nevertheless, resist such axial movement so that a tension may be taken on the pipe to which one of the parts is connected and when the restraining means is overcome that part may be elevated by the tension or stretch in the pipe to impart a sharp blow to the other part.

More specifically, an object of the invention is to provide a jar wherein the restraining means is equally distributed about the vertical axis through the two parts so that the jar may be operated merely by a straight pull and stresses will be evenly distributed about the axis. Still another object of the invention is to provide a jar having the above-mentioned characteristics wherein the resistance offered by the restraining means is capable of adjustment and in addition, the adjustment may be made while the jar is in the well.

Wtih the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure 1 is a vertical section through the jar embodying the present invention illustrating the parts in the position assumed thereby prior to efiecting a jar on the fish or stuck pipe;

Fig. 2 is a partial view in vertical section illustrating positions assumed by some of the parts after a jar has been efiected;

Fig. 3 is a horizontal section taken substantially upon the line 3-3 upon Fig. 1 in the direction indicated; and

Fig. 4 is a horizontal section taken substantially upon the line 44 upon Fig. l in the direction indicated.

.Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved jar comprises an inner mandrel generally indicated at 10, telescopically arranged within an outer sleeve that may be regarded as being principally made up of sections 11, 12, 13, and 14. This sleeve is made. upof sections primarily for the purpose of facilitating construction. The sections are mutually connected together by means of threaded joints.

The upper end of the mandrel has a threaded pin which is screwed into a sub 16 that presents a threaded pin 17 by which the mandrel and sub may be connected to a string of drill pipe. About halfway down the mandrel,'the mandrel is externally enlarged as at 18 and cylindrically formed so as to slidingly fit the interior of the section 11 of the sleeve. Above this enlargement the mandrel is hexagonally formed as indicated at 19 and slidably extends through a complementary hexagonal opening 20 formed on an internal shoulder 21 on the upper part 11 of the sleeve. This hexagonal fit between the upper portion and the mandrel and the interior of the shoulder 21 forms a type of splined connection between the mandrel and the sleeve enabling the sleeve to be rotated by the mandrel and at the same time permitting a limited axial movement between the mandrel and the sleeve. Upward movement of the mandrel with relation to the sleeve is limited by the engagement of the top of the cylindrical portion 18 with the bottom of the shoulder 21. Y

The section 12 of the sleeve is internally enlarged as indicated at 22 to receive a generally cylindrical spring restrainer. This spring is in the form of a spring steel cylinder the center of which is bowed inwardly as indicated at 23. The spring is divided by vertical slots 24 into segments 25. These slots extend from near the top of the cylinder to near the bottom of the cylinder, and although the segments are all integrally connected together, they are capable of being independently or separately flexed outwardly from their normal inwardly bowed position.

The spring restrainer may be otherwise described as a resilient, annular, longitudinally elongated member having a plurality of substantially longitudinally extending circumferentially spaced slots which define a plurality of normally inwardly bowed segments.

Opposite the interior of the spring restrainer the mandrel is equipped with a plurality of radial slots 26, and in each of these slots there are disposed balls 27. Within the balls there is disposed a cone 28 that is threaded into the bottom of the mandrel as indicated at 29. This cone, on being screwed upwardly in the mandrel, will serve to expand or crowd the balls 27 outwardly toward the spring restrainer. Conversely, if the cone is screwed downwardly with relation to the mandrel it permits the balls to contract or assume inner positions in their respective slots 26.

The bottom of the cone is provided with clutch elements 30 which are complementary to and are engageable with clutch elements 31 on a cap 32 that is mounted on top of a sub 33 that slidably extends through the lowermost part 14 of the outer sleeve. The sub is equipped with a threaded pin 34 by which it may be attached to a fishing tool or to a string of pipe extending downwardly below the jar. The sub 33 is slidable and also rotatable within the part 14 of the sleeve. A wash pipe 35 extends downwardly through the mandrel and is retained in position on the sub 16 by being flanged and held in place as by a holow nut 36. This wash pipe extends downwardly through the mandrel and through the sub 33. In the sub 33 there is disposed packing 37 which is compressed about the Wash pipe, such as by a nut 38.

The operation of the jar is substantially as follows:

The fishing tool or string of pipe connected to the sub 33 is assumed to have become either immovably lodged in the well or held against vertical movement therein.

With the parts of thejar in the position as shown in Fig.

1, the upper string of drill pipe connected to the sub 16 may have an upward tension applied thereto which is of considerable magnitude and which is capable of stretching the pipe to some extent. Upward movement of the mandrel 10 with this pipe is resisted by reason of the wedging action of the balls 27 between the cone 28 and the segments 25 of-the spring restrainer. As the tension on the pipe is increased, and consequently the stretch of the pipe is increased, this wedging action becomes so great that eventually the segments 25 are flexed outwardly from.

their inwardly bowed positions sufiicient so that the balls may passwithin the innermost portions 23 of the restrainer. As the balls pass these innermost portions the resistance to upward movement of the mandrel 10 is suddenly released and the contraction of the stretched pipe is such as to cause the mandrel to be suddenly elevated. This carries the cylindrical portion 18 into engagement with the shoulder 21 imparting a sharp upward blow to the shoulder. If the initial blow is insufficient to loosen the stuck pipe or to jar loose the fish, the mandrel 10 may again be lowered by the pipe thereabove, and inso doing, the balls 27 merely move upwardly against the cone 28 in passing over the innermost portions 23 of the restrainer. The parts can thus be returned to the nosition shown in Fig. l and the operation repeated.

In many situations it may be found that the resistance afforded by the restrainer is either too great or too weak to meet the requirements of the conditions under which the jar isbeing operated. If this occurs,.the string of drill pipe connected to the sub 16 maybe lowered, lowering both the mandrel 10 and its surrounding sleeve relative to the sub 33, causing the clutch elements 30 and 31 to mutually engage. When these clutch elements have been engaged the pipe may be rotated, which causes the cone 28 to be either screwed upwardly in the mandrel 10 or screwed downwardly therefrom, depending upon the direction 0t rotation. The sub 33 being held stationary by the stuck pipe or by the fish causes the cone 28 to be held stationary therewith while the mandrel is being rotated relatively thereto.

If the cone is screwed upwardly into the mandrel this has the effect of expanding the balls or moving them out into closer engagement with the segments 25 of the restrainer. Consequently, under these conditions a greater upward force is necessary to pull the balls through the restrainer than initially. On the other hand, if cone 28 is screwed downwardly with relation to the mandrel 10 it permits the balls to contract, and consequently less upward force is necessary to pull the balls through the restrainer than initially. In this manner, it will be appreciated that the cone 28 can be adjusted on thejar while the jar is in the well to meet various conditions. Consequently, the proper upward tension and the proper stretch of the pipe can be caused to take place before the balls pass over the innermost portions 23 of the restrainer and effect a release of the mandrel for upward movement. It will be appreciated that at. any time circulation fluid may be forced down through the pipe and through the wash pipe. 35. During reciprocatory movements of the mandrel 10 relative to the sleeve the wash pipe merely slides throughthe packing 37.

The above-described construction is primarily used in fishing operations, but it will be appreciated that the jar may be readily converted into a drilling jar adapted to be incorporated. in the rotary drill string if desired. Under such circumstances the lowermost part 14-01. the sleeve and the sub 33 may be dispensed with. and the part 13 of the sleeve connected directly to the drill pipe therebelow. Torque on the upper string of drill pipe is transmitted through the sub 16 to the mandrel 10 and from the mandrel 10 through the sleeve parts 11, 12, and 13, directly to the drill pipe therebeneath. Under such circumstances, it is important, of course, to effect an adjustment of the. cone 28 while in the well and the position of thecone with. relation to the balls and to the spring restrainer must be set prior to the introduction of the jar into the well, and will,.of course, have to remain in that position of adjustment while the jar is in the well.

It will be appreciated from the. above-described construction that a jarring operation can be. performed by means of a direct or straight pull on the upper string of drill pipe. Stresses occasioned thereby are equally distributed about the longitudinal or vertical axis of the jar. Resistance to upward movement of the mandrel relative to the sleeve is likewise equally distributed and the. release is distributed with relation to this axis. The blowimparted to the shoulder 21 by the cylindrical portion 18' is equally distributed and equally conducted down the sides of the sleeve to the sub 33 or to the drill pipe beneath the jar as the case may be.

It will thus be appreciated that the improved jar is of relatively simple construction andmay be easily manufactured and assembled. The number of parts thereof is relatively small and these parts are readily accessible for replacement and repair in the event of any injury to the tool. While the inward force exerted by each of the segments 25 of the cylindrical restrainer is individually small, collectively this force acting on all of the balls 27 is so great that resistance to upward movement of the mandrel relatively to the sleeve is such that an adequate tension and adequate stretch of the pipe above the jar may be obtained before a release of the jar takes place.

Various changes may be made in the details of construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A rotary jar comprising an inner mandrel having an enlargement thereon, a sleeve telescopically arranged about the mandrel having an internal shoulder engageable by the mandrels enlargement, a substantially cylindrical spring within the sleeve vertically divided into inwardly bowed segments, each of which is capable of being flexed outwardly, balls in slots in the mandrel engageable with said segments to flex the segments outwardly when the balls are moved through the cylindrical spring, and a cone on the mandrel for holding the balls in engagement with said segments.

2. A rotary jar comprising an inner mandrel having an enlargement thereon, a sleeve telescopically arranged about the mandrel having an internal. shoulder engageable by the mandrels enlargement, a substantially cyline drical spring within the sleeve vertically divided into inwardly bowed segments, each of which is capable of being flexed outwardly, balls in slots in the mandrel engageable with said segments to flex the segments outwardly whenthe balls. are moved through the cylindrical spring, a cone on the mandrel for holding the balls in engagement with. said segments, said cone being. threaded into the mandrel and having clutch elements thereon, and a sub having, a rotary and limited slidable movement relatively to the sleeve presenting complementary clutch elements engageable with the clutch elements on the cone. I

3. A jar comprising two telescopically arranged members having a limited axial movement relative to each other, a cylindrical spring restrainer on the interior of the outer member having segments normally bowed inwardly but capable of being flexed outwardly, balls engageable with the inner sides of said segments adapted to flex them outwardly when the balls are moved therethrough, a cone secured to the inner of said members for holding the balls adjacent the inner sides. of the segments, and means for holding the balls about the cone.

4. A jar comprising two telescopic members movable axially relative to each other, means limiting said axial movement, means resisting said axial movement but per-- mitting such. movement only after an adequate load is imposed on one member tending to move it axially relative to the other comprising a resilient annular, longitudinally elongated member mounted on one of the telescopic members and having a plurality of substantially longitudinally extending, circumferentially spaced slots. defining. from. each other a plurality of segments normally bowed inwardly but being capable of beingflexedoutwardly, and. means on the other of said telescopic members adapted to be moved through said resilient annular, longitudinally elongated member and in so doing to flex said segments outwardly when said load is imposed.

5. A. jar comprising two telescopic members movable axially relative to each other, means limiting said axial movement, means resisting said axial movement but permitting such. movement only after an adequate load is imposed on one member tending to move it axially relative to the other comprising a resilient annular, longitudinally elongated member mounted on one of the telescopic members and having a plurality of substantially longitudinally extending, circumferentially spaced slots defining from each other a plurality of segments normally bowed inwardly but being capable of being flexed outwardly, and means on the other of said telescopic members adapted to be moved through said resilient annular, longitudinally elongated member and in so doing to flex said segments outwardly when said load is imposed, the last-mentioned means being expansible whereby the load required may be varied.

6. A jar comprising inner and outer telescopic members movable axially relative to each other, means limiting said axial movement, means resisting said axial move ment but permitting such movement only after an adequate load is imposed on one member tending to move it axially relative to the other comprising a resilient annular, longitudinally elongated member having a plurality of substantially longitudinally extending, circumferentially spaced slots defining a plurality of segments, said resilient annular, longitudinal elongated member being mounted on the interior of the outer of said telescopic members and said segments being normally bowed inwardly, balls on the inner of said telescopic members engageable with the segments adapted to flex them outwardly when said load is imposed, and a cone on the inner member for holding the balls in position to engage the inwardly bowed segments.

7. A jar comprising inner and outer telescopic members movable axially relative to each other, means limiting said axial movement, means resisting said axial movement but permitting such movement only after an adequate load is imposed on one member tending to move it axially relative to the other comprising a resilient annular, longitudinally elongated member having a plurality of substantially longitudinally extending, circumferentially spaced slots defining a plurality of segments, said resilient annular, longitudinal elongated member being mounted on the interior of the outer of said telescopic members and said segments being normally bowed inwardly, balls on the inner of said telescopic members engageable with the segments adapted to flex them outwardly when said load is imposed, and a cone on the inner member for holding the balls in position to engage the inwardly bowed segments, said cone being axially adjustable relatively to the inner of said telescopic members whereby the positions of the balls radially of the inner telescopic member may be varied.

8. A jar comprising inner and outer telescopic mem bers movable axially relative to each other, means limiting said axial movement, means resisting said axial movement but permitting such movement only after an adequate load is imposed on one member tending to move it axially relative to the other comprising a resilient annular, longitudinally elongated member having a plurality of substantially longitudinally extending, circumferentially spaced slots defining a plurality of segments which are normally bowed inwardly, said resilient annular, longitudinally elongated member being mounted on the interior of the outer of said telescopic members, balls on the inner of said telescopic members engageable with the segments adapted to flex them outwardly when said load is imposed, a cone on the inner telescopic member for holding the balls in position to engage the segments, a clutch element on the cone, and a complementary clutch element engageable therewith having a rotary and limited axial connection with the outer telescopic member whereby the inner and outer telescopic members may be moved axially to engage the clutch elements and by rotation of the inner telescopic member relatively to said complementary clutch element the position of the cone and of the balls may be varied while the jar is in a well.

9. A. jar comprising inner and outer telescopic members, means limiting axial movement of said telescopic members relative to each other, means on the interior oi the outer telescopic member permitting but resisting axial movement of one telescopic member relative to the other until an adequate load tending to produce such movement is imposed, a threaded member having a rotary and limited axial connection with the outer of said telescopic members, and means operable by lowering both of said telescopic members relatively to the third member and rotating the telescopic members relatively thereto for varying the resistance to moving one of the telescopic members axially with respect to the other.

10. A jar comprising inner and outer telescopic members having a limited axial movement relative to each other, a cylindrical spring restrainer on the interior of the outer member having segments normally bowed inwardly but capable of being flexed outwardly, balls engageable with the inner sides of said segments adapted to flex them outwardly when the balls are moved therethrough, a cone secured to the inner telescopic member for holding the balls adjacent the inner sides of the segments, means for holding the balls about the cone, said cone being threaded onto the inner of said telescopic members, a third member having a rotary and limited axial connection with the outer of said telescopic members and clutch means between the cone and said third member whereby upon engagement of the clutch and rotation of said telescopic members the balls may be radially expanded by the cone.

References Cited in the file of this patent UNITED STATES PATENTS 1,895,227 McCullough Jan. 24, 1933 1,989,906 Beck Feb. 5, 1935 1,989,907 Beck Feb. 5, 1935 2,025,944 Fisher Dec. 31, 1935 2,557,238 Shaffer June 19, 1951 

